When changes occur within the main Global Address Book (GAL) on the Office 365, computers running Outlook 2016 may not automatically receive the updates. If this is happening, then you may notice missing, non-existent and/or incorrect entries. Synchronizing your Outlook (cached) address book with the Global Address book may fix these discrepancies. Instances of mail that is bounced back to the sender may also be fixed.

*Note: Outlook 2016 for Mac automatically updates every 24 hours.

Global Address Book Update.

  • Click File > Account Settings > Download Address Book...

  • In the Offline Address Book dialog box, make sure that the Download changes since last Send/Receive check box is un-checked.

  • Click OK
  • The Outlook Global Address Book update will take about 5 minutes.